1. Technical Field
The invention relates to a thrust washer in the form of a semi-circular flanged ring with at least two radially inward-directed outer connection pieces on the inner edge of the thrust washer for the connection with a radial bearing part, which are located in the circumferential direction on both sides of a contrived centerline of the thrust washer and in each case have an inner edge facing the centerline and an outer edge turned away from the centerline. The invention also relates to a radial-axial bearing with a radial bearing part and a thrust washer of such a type connected with the radial bearing part.
2. Related Art
Radial-axial bearings are used, for example, in the manufacture of engines such as crankshaft bearings or the like. The radial bearing part can be designed as semi-cylindrical bearing shells or bushings. The radial-axial bearing can be connected to one or both frontal (axial) ends in each case with a thrust washer. The designation “semi-circular flange ring” also includes in terms of the invention such forms of the thrust washer, whose ends actually go beyond the bisecting partial plane or chord. Such forms are known, for example, from EP 1 320 690 A and serve to augment the surface of the thrust washer or as an assembling aid.
Basically two types of construction are known for the connection of the thrust washer(s) with the radial bearing part. In the case of so-called built-up bearings the radial bearing part and the thrust washer are latched with each other in a positive-locking and undetachable manner by means of correspondingly configured plates at the thrust washer and corresponding retaining openings at the radial bearing part. Embodiments of such built-up bearings are known, for example, from DE 43 03 855 C1, DE 33 45 652 A1, DE 41 40 277 A1 or EP 0 307 984 A2. The assembly of the bearing (subsequently the assembly of the axial and the radial bearing part to form a radial-axial bearing is designated by the term “assembly”) requires a special tool or a specially equipped assembly machine due to the complex supply and latching movement or due to the additional working steps, in which the latches are fixed in place after the components are brought together. Therefore, the assembly is not infrequently carried out through manual intervention. Furthermore, the connection pieces and/or retaining openings have complicated and for this reason expensive geometries from a manufacturing standpoint, which ensure a secure connection between both of the components in the latched state.
In the second type of construction the radial-axial bearings are welded with each other. The radial bearing part in this type of construction has frontal recesses, in which the connection pieces of the thrust washer are inserted in the axial supply direction.
As a rule, a bearing half-shell has a spread angle, i.e., its basic shape, in contrast to the thrust washer is not precisely semi-circular, but rather is slightly bent open (as a rule a few tenths of a millimeter). The spread angle is removed during the mounting of the half-bearing in the bearing seat of a bearing housing or cover provided therefore (subsequently only precisely this is designated by the term “mounting”), so that the bearing shell is elastically compressed. Through the elastic reset force traction is achieved between the bearing shell and the bearing seat, which fixes the bearing shell in the mounted state and thus facilitates the mounting.
Generally, the spread angle must be removed beforehand depending on the geometry of the connection piece also during the assembly of the bearing shell and the thrust washer, until the connection pieces and the recesses align. Also here the elastic reset force after the assembly arranges for a force-fit cohesion of bearing shell and thrust washer. However, if the spread angle is already removed by the assembly of the bearing, the traction described above no longer or not sufficiently adjusts itself to the bearing seat during the mounting.
Since the thrust washer and the bearing half-shell in this type of construction are indeed connected with each other after the assembly as a rule in a force-locking, but not undetachable manner, they are connected with each other after being brought together at one or several locations of the outer circumference of the bearing half-shell on the face by welding. As an example, reference is made to DE-OS 25 28 576 A1 or DE-OS 24 12 870 A1 (the latter without explicit indication of a welded connection). It is disadvantageous, that also here a special assembly device is needed, which provides for a despreading of the bearing half-shell, and a special assembly machine is required equipped for the axial supply of the thrust washer.
A radial-axial slide bearing is known from DE 40 15 256 A1, in which the thrust washer has at least one radial dovetail-shaped connection piece, projecting inwards, which engages in a complementary recess of the radial bearing part, which tapers in the radial direction. The recess is therefore adjusted in the radial direction to the inclination of the arm and outer edges of the dovetail-shaped fastening piece, so that the axial bearing part is fixed both in the circumferential direction as well as in the radial direction with regard to the radial bearing part.
DE 198 25 117 A1 discloses a radial-axial bearing, with which the connection pieces of the thrust washer are formed free of undercuts in the radial direction through the summit of the flanged bearing shell or viewed in parallel thereto and are importable in this direction into retaining openings enclosed on all sides in the radial bearing part.
A flanged bearing shell is known from GB 2 225 392, in which the thrust washer has a connection piece conically tapered away in the axial direction from the radial bearing part. The assembly of both parts occurs, as the thrust washer with the retaining plate is inserted into a rectangular frontal recess in the radial bearing part and the corners of the recess are subsequently recast so that they form an undercut and fix the wedge-shaped connection piece in the axial direction.